I did have one doctor who would have his office staff call you if he was running really late. You had a choice of coming in later, or rescheduling. This was way before cell phones, and if you were running errands before your appointment, and had already left home, it didn't do much good. But, I was given the opportunity to leave the office and come back later without loosing my place in line.
When I was a kid the doctor didn't make appointments. He had office hours, and you showed up. You were expected to remember your place in line, no lists were made. He would stick his head out of his exam room door, and the next person in line would get up and go in. It was just him and his nurse (who was also his wife). I remember long waits, but since I was a kid, they might not have been that bad.